But it’s not just these two mostly suburban categories where Democrats could pick up seats. Two of the other four CityLab categories also contain districts that are somewhat suburban and could be pickups for Democrats. We’re talking about places like the Florida 27th — a mix of urban areas with some denser suburbs — and the Kentucky 6th — suburban and rural with little or no urban area — that respectively fall into the “Urban-Suburban Mix” and “Rural-Suburban Mix” groups. Together, they make up 37 percent of House districts, and if we combine them with the two predominantly suburban categories, you could say that almost every district where Democrats are favored to make gains has notable suburban characteristics, with just three potential pickups coming from “Pure Rural” seats.6 (Note: The oft-discussed Obama-Trump and Romney-Clinton districts both overlap with these suburban categories.)

Also, while Democrats are struggling to make significant gains in more rural parts of the country, you can see their potential in urban areas is practically maxed out,7 making their drive to pick up suburban seats all the more pressing.